Optical UV lamp-on indicator

ABSTRACT

An observable optical lamp status display system is provided for an ultraviolet irradiation lamp concealed from view. An external lamp status display panel that is within the field of view of an observer registers the operating status of each ultraviolet light irradiation lamp in an array of irradiation lamps. A separate fiberoptic lamp status display filament extends between each ultraviolet radiation lamps and the display panel. The lamp status display filament has a first end terminated in optical communication with the ultraviolet lamp and an opposite end that terminates at an optical sensor in the lamp status display panel. An observer can determine whether or not a lamp is operating simply by observing the output of the optical sensor in the display panel for each lamp operated.

CROSS-REFERENCES TO RELATED APPLICATIONS

This patent application claims the benefit of U.S. patent applicationSer. No. 11/644,800 filed Dec. 21, 2006 for OPTICAL UV LAMP-ONINDICATOR, which application is incorporated here by this reference.

TECHNICAL FIELD

This invention relates to a system for displaying the status ofoperation of shielded ultraviolet irradiation lamps using fiberopticfilaments.

BACKGROUND ART

Ultraviolet radiation lamps are widely utilized in many differentindustries for irradiating different substances with ultravioletradiation. UV lamps are utilized to kill bacteria in food and water, andalso on the packaging for food and beverage products. Ultravioletirradiation lamps are utilized to treat food packaging products such asdairy product cartons, lids, sealing films, plastic wrap, labels,reusable product containers and other articles used in the packaging ofproducts, as well as in the sanitization of food and beverages itemsthemselves.

In conventional ultraviolet bacteria irradiation treatment a pluralityof ultraviolet lamps are typically positioned within an enclosurethrough which the materials to be sanitized by UV irradiation arepassed. As the material to be treated is advanced past the stationaryultraviolet lamps, either by fluid flow or by some apparatus forconveyance, the material to be treated passes in close proximity to thelamps. Ultraviolet radiation emitted by the lamps kills bacteria,microbes, and other harmful biological contaminants.

Because ultraviolet radiation is harmful to the human operators of thesanitizing equipment, it is important for the enclosures containing theultraviolet radiation lamps to be shielded to prevent harmful UVradiation from being directed at the equipment operators and otherindividuals in the vicinity. UV radiation can be particularly damagingto a person's eyesight.

The most inexpensive type of shielding is some type of opaque substance,such as metal or thick plastic which resists penetration to bothultraviolet radiation and also visible light. As a consequence, theultraviolet lamps that irradiate the materials to be treated arenormally concealed from view and are not directly observable by theequipment operators. Shielding avoids exposure to harmful radiation,especially damage to the eyes of the equipment operators.

However, since it is typically not possible to observe the ultravioletlamps in operation, a lamp can cease to emit ultraviolet radiationwithout being noticed by the equipment operators. If a nonfunctionalultraviolet lamp is left in position, material to be treated flows pastit, but is not subjected to sufficient ultraviolet radiation.Consequently, while the equipment operators may think that the system iseffectively performing its irradiation function, in fact, some of thematerial passing through the system may be untreated or treatedinadequately.

To remedy this situation conventional electronic systems have beendevised to display the operational status of ultraviolet radiation tubesto the equipment operators at a status display panel. In such systemselectronic circuits are embodied in the ultraviolet lamp couplingsthrough which power is provided to generate ultraviolet radiation. Theelectrical power utilized to produce the required ultraviolet radiationalso serves to provide an operational status indication for eachultraviolet lamp to the equipment operators.

While such electronic status indicators do perform the desired functionof displaying to the equipment operators the operational status of thedifferent ultraviolet lamps, these circuits are unnecessarily complexand therefore expensive. Furthermore, these sensing circuits canmalfunction and provide either false positive or false negativeindications which disrupt the efficient throughput of materials to betreated.

DISCLOSURE OF INVENTION

The present invention provides a display system for monitoring thestatus of ultraviolet lamps that does not require any electrical sensingcircuitry whatsoever. To the contrary, the lamp display system of thepresent invention operates entirely on an optical basis. That is, asmall portion of the visible light that is generated concurrently withultraviolet radiation from a lamp is directed to a display panel. Thisis achieved through the use of a fiberoptic filament associated witheach lamp. The fiberoptic filament has opposing light input and lightoutput ends. The light input end is placed in optical communication withthe ultraviolet lamp to be monitored. The light output end of thefilament terminates at a display panel or other location that canobserved by operators of the equipment.

Typical fiberglass fiberoptic filaments are fabricated so that theyblock ultraviolet radiation, while transmitting visible light. Moreover,the fiberoptic filaments do not have to extend in a straight line, butcan be bent and contoured as necessary to extend between a position ofoptical communication with the ultraviolet lamp to be monitored and thelamp display panel or other monitoring position.

In one broad aspect the present invention may be considered to be animprovement in an ultraviolet light irradiation apparatus including anultraviolet light irradiation lamp concealed from view and an external,observable lamp status display panel. According to the improvement ofthe invention a fiberoptic lamp status display filament is providedhaving a first end terminated in optical communication with theultraviolet lamp and an opposite, second end terminated at a lightsensor in the lamp status display panel. Preferably, the end of theultraviolet light irradiation lamp located proximate to the first end ofthe display filament is terminated in a ceramic base with a tunneldefined therethrough and which receives the ultraviolet radiation lamp.A lamp connector that supplies electrical operating power to the lamp isalso provided. The lamp connector provides a seat for the ceramic base.The first end of the lamp status display filament terminates in the lampconnector and is in optical communication with the lamp through thetunnel defined through the base.

The tunnel is preferably a linear cylindrical passage having a circular,cross section and is defined through the base between its opposing ends.The tunnel conducts visible and ultraviolet light from the ultravioletirradiation lamp to the first end of the fiberoptic filament. Thefiberoptic filament is comprised of a material that passes visible lightwhile blocking, or at least significantly reducing, the transmission ofultraviolet radiation.

In another broad aspect the invention may be considered to be a powerstatus indicator for an ultraviolet irradiation lamp mounted in a basethat has a lamp receiving end and a power input end. The base is coupledto a lamp connector that is supplied with electrical power from a powercord connected thereto. A straight, linear light tunnel is defined inthe base and extends between the lamp receiving end and the power inputend of the base. The tunnel is in optical communication with theultraviolet lamp. A fiberoptic filament is provided. The fiberopticfilament has a light input end terminating in the lamp connector inoptical communication with the light tunnel through the base. Thefiberoptic filament also has an opposite light output end that providesa lamp status display to an observer, the lamp status display includinga photosensor in optical communication with the light output of thefiberoptic filament.

The fiberoptic filament suppresses transmission of ultraviolet radiationwhile facilitating transmission of visible light. The base and the lampconnector are preferably releaseably joined together.

In still another broad aspect the invention may be considered to be animprovement in an array of ultraviolet light irradiation lamps, each ofwhich is mounted in a separate base and which is provided withelectrical operating power through a separate lamp connector dedicatedthereto. According to the improvement of the invention a straight lighttunnel is provided through each of the bases. Each tunnel is in opticalcommunication with its associated ultraviolet lamp. A separatefiberoptic filament is provided for each lamp. Each filament has a lightinput end terminating in a single one of the lamp connectors and inoptical communication with a single one of the light tunnels. Eachfiberoptic filament has an opposite display end terminated in a lightsensing circuit in a status display panel.

Each of the fiberoptic filaments transmits visible light and preferablyattenuates ultraviolet radiation.

The invention may be described with greater clarity and particularity byreference to the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a side elevational view illustrating a portion of a singlepower status indicator for a single ultraviolet lamp constructedaccording to the invention.

FIG. 2 is a sectional elevational view of the status indicator of FIG.1.

FIG. 3 is an enlarged detail of a single connector, shown partially insection.

FIG. 4 is a sectional elevation view taken along the lines 4-4 of FIG.2.

FIG. 5 illustrates one embodiment of a display panel according to theinvention.

FIG. 6 illustrates an alternative embodiment of a display panelaccording to the invention.

FIG. 7 illustrates and array of display panels of the type illustratedin FIG. 6 as coupled to a typical ultraviolet irradiation system.

FIG. 8 is a side elevational view of the device illustrated in FIG. 1and also including a light sensor.

FIG. 9 is an electrical schematic showing a version of a circuit for anoptical sensor.

BEST MODE FOR CARRYING OUT THE INVENTION

The detailed description set forth below in connection with the appendeddrawings is intended as a description of presently-preferred embodimentsof the invention and is not intended to represent the only forms inwhich the present invention may be constructed or utilized. Thedescription sets forth the functions and the sequence of steps forconstructing and operating the invention in connection with theillustrated embodiments. However, it is to be understood that the sameor equivalent functions and sequences may be accomplished by differentembodiments that are also intended to be encompassed within the spiritand scope of the invention.

FIGS. 1-4 illustrate an ultraviolet light irradiation apparatusindicated generally at 10. The irradiation apparatus 10 includes anultraviolet light irradiation lamp 12, the power input end 14 of whichis visible in FIG. 2. The ultraviolet irradiation lamp 12 is concealedfrom view by a metal partition 16. In the area 18 on the side of thepartition 16 in which the UV lamp 12 is mounted, materials moving pastthe UV lamp 12 perpendicular to the plane of drawing FIGS. 1 and 2 isirradiated by the ultraviolet irradiation UV lamp 12. For example, theregion 18 may be the interior of a duct through which water flows and istreated to kill bacteria in the water by irradiation using theultraviolet irradiation UV lamp 12, and typically a plurality ofidentical lamps of the type illustrated.

System operators and observers are located on the opposite side of thepartition 16 in the region indicated at 20. The metal partition 16 isconstructed of a material that shields personnel in the region 20 fromultraviolet radiation produced by the UV lamp 12.

At each lamp position there is a mounting aperture 22 in the partition16 through which each UV lamp 12 is inserted. A hollow nipple 24 islocated within each aperture 22. The nipple 24 is engaged by externalthreads with internal threads in an annular collar 26 which captures aflange 28 of a coupling 30 constructed according to the presentinvention. The coupling 30 has an outer shell 32 and the flange 28 isformed at the open end of the shell 32. The coupling 30 also includes anelectrically insulating internal core 34 into which electricallyconductive sockets 36 are embedded. The electrically conductive sockets36 are connected to wires 38 that are encased within a power cord 40that leads to an electrical power supply.

The ultraviolet radiation lamp 12 is mounted in a ceramic base 42 whichhas a lamp receiving end 44 and an opposite, power input end 46. Theelectrical contacts for the lamp 12 are connected to a pair oflongitudinally extending plug pins 48 at the lamp receiving end 44 ofthe ceramic base 42. The electrical plug pins 48 extend longitudinallyfrom the lamp receiving end 44 of the ceramic base 42 and project beyondthe power input end 46 of the ceramic base 42. The projecting portionsof the plug pins 48 that protrude out of the power input end 46 of theceramic base 42 have a diameter and are spaced apart an appropriatedistance to both fit snugly into the electrical sockets 36 embeddedwithin the lamp connector 30. The power input end 46 of the ceramic base42 has an outer cross-sectional area that fits snugly into the embraceof the flange 28, so that the connector 30 and ceramic base 42 aresnugly, but releaseably coupled together. A rubber gasket 50 isinterposed between the ceramic base 42 and the interior surface of thenipple 24 to create a fluid-tight seal to prevent any fluid fromescaping the area 18 through the aperture 22.

The foregoing features of the power status indicator 10 thus fardescribed are conventional and different variations exist within theultraviolet irradiation industry for connecting ultraviolet irradiationlamps to an electrical power supply. The improvement of the inventionresides in the provision of a narrow, cylindrical, fiberoptic filament52 that has a light input end 54 that is embedded within and extends thelength of the lamp connector 30. The opposite output end 56 of thefiberoptic filament 52 provides a visible lamp status display to anobserver. Typically the light output end 56 of the fiberoptic filament52 terminates in a display panel, indicated at 58 in FIGS. 1 and 2.

The ceramic base 42 is provided with a longitudinally extending,cylindrical tunnel 60 defined throughout its length from the lampreceiving end 44 to the opposite power input end 46. The light tunnel 60is simply an open passage of circular cross section and straight,linear, cylindrical shape that extends the entire length of the ceramicbase 42. When the electrical power plug pins 48 are inserted into thesockets 36, the light tunnel 60 is coaxially aligned with thetermination of the light input end 54 of the fiberoptic filament 52. Asa consequence, both visible and ultraviolet radiation easily passthrough the light tunnel 60.

When visible and ultraviolet light reach the light input end 54 of thefiberoptic filament 52, the fiberoptic filament 52 serves as a filterthat transmits visible light while largely blocking ultravioletradiation. Visible light that enters the light input end 54 of thefiberoptic filament 52 passes longitudinally along the length of thefiberoptic filament 52 and is observable to a system operator orinspector at the termination of the display end 56 of the fiberopticfilament in the display panel 58.

While the fiberoptic filament 52 has been illustrated as having astraight, linear shape in FIGS. 1 and 2, it is to be understood that thefiberoptic filament 52 can be bent through significant angles and followa circuitous route before reaching the display panel 58. Irrespective ofthe manner in which the fiberoptic filament 52 is routed from theconnector 30 to the display panel 58, visible light will travelunimpeded along the entire length of the fiberoptic filament 52, just aswater travels through an open pipe.

Once the ceramic bases 42 of the ultraviolet lamps 12 have been insertedinto their respective openings 22, power is provided to the lamps 12 byconnecting to each lamp 12 a dedicated releaseable coupling 30. That is,the releaseable coupling 30 is inserted so that the annular flange 28surrounds and engages the power input ends of the ceramic bases 42. Asthe couplings 30 are pushed onto the power input ends 46 of the ceramicbases 42 the electrically conductive plug prongs 48 extending from thepower input ends 46 of the ceramic bases 42 are received by the sockets36 to establish an electrical connection to the lamps 12 from the powersupply that supplies electricity through the power cord 40.

The connectors 30 are releaseably coupled to the bases 42 of the lamps12 by means of the internally threaded collars 26 which are screwed ontothe externally threaded nipples 24. The lamp connector 30 therebysupplies electrical operating power to its associated ultravioletirradiation lamp 12. Concurrently, the light input end 54 of thefiberoptic filament 52 is aligned with the light tunnel 60 so that oncepower is turned on to the ultraviolet irradiation tube 12, visible lightwill be transmitted from the light input end 54 of the fiberopticfilament 52, along the entire length of the fiberoptic filament 52 tothe light output end 56 thereof in the display panel 58 or 62.

The ultraviolet light irradiation lamp 12 is concealed from view from anobserver of the external lamp status display panel 58 or 62. The firstend 54 of the lamp status display filament 52 is terminated within thecoupling 30 in optical communication with the ultraviolet lamp 12. Theopposite, second end 56 of the lamp status display filament 52 isterminated in the lamp status display panel 58 or 62. The ceramic base42 receives the ultraviolet radiation lamp 12 and in turn is nested intothe lamp connector 30. The lamp connector 30 supplies electricaloperating power to the lamp 12. The first end 54 of the lamp statusdisplay filament 52 terminates in the lamp connector 30 so that it is inoptical communication with the lamp 12 through the tunnel 60.

Consequently, and as indicated in FIG. 5, the light output ends 56 of anumber of different fiberoptic filaments 52 can be brought together inan appropriate display panel. The display panel may have a circularshape, such as the display panel 58 indicated in FIG. 5.

The panel 58 is a typical arrangement for an array of ultravioletirradiation lamps 12 that are located within a closed vessel 59.Typically there are between six and fifty-six ultraviolet lamps 12mounted within the vessel 59, each of which is provided with a separatefiberoptic filament 52 that is dedicated to each ultraviolet lamp 12.The fiberoptic filaments are routed so that their light output ends 56terminate in close proximity to each other, preferably in a mannerindicative of their positions within the vessel 59.

Alternatively, the light output ends 56 of the fiberoptic filaments 52may terminate in a display panel 62 in which the light output ends 56 ofa plurality of fiberoptic filaments 52 terminate in a linear array, asillustrated in FIG. 6. In a typical water irradiation system there areoften eight individual fiberoptic filaments 52, each dedicated to asingle ultraviolet irradiation lamp 12, and terminating together in alinear array in a display panel 62. The display panels 62 may containthe light output ends 56 of a group of eight or any other number offiberoptic filaments 52, as illustrated in FIG. 6. Where a multiplicityof ultraviolet irradiation tubes 12 are employed, a number of thedisplay panels 62 may be arranged in separate power distribution andcontrol modules 66 in a side-by-side array, as illustrated in FIG. 7.

The arrangement illustrated in FIG. 7 is typical of an installation ofthe type employed in irradiating water flowing through a laterallyenclosed channel. The display panels 62 are typically the transverse,exposed ends of slide-out shelves 68 that are secured by screws 70 thatreleaseably hold the shelves 68 in place in a module 66. In a typicalmodule 66 circuit protection is provided by a fuse in a main circuitbreaker (not shown) on each shelf. These features are conventional.

When a single ultraviolet irradiation lamp 12 or, more typically, aplurality of ultraviolet irradiation lamps 12 of the type illustrated inFIG. 2 are in operation, the lamps 12 irradiate fluid or other materialspassing through or constrained within a laterally shielded irradiationchamber 18. When the ultraviolet irradiation lamps 12 are providingultraviolet radiation, they also provide a certain amount of visiblelight as well. Some of this visible light travels through the lighttunnel 60 in the ceramic base 42. This visible light enters the first,light input end 54 of the fiberoptic filament 52 dedicated to thatultraviolet irradiation lamp 12. The fiberoptic filament 52 facilitatesand passes visible light that it receives from the light tunnel 60 whilesuppressing or blocking ultraviolet radiation. As a consequence, little,if any, ultraviolet radiation emanates from the light output end 56 ofthe fiberoptic filaments 52.

It is evident that if all of the ultraviolet irradiation lamps 12 areilluminated and providing ultraviolet radiation, there will be a lightoutput from all of the light output ends 56 of all of the fiberopticfilaments 52 terminating in the display panels 58 or 62. On the otherhand, should any ultraviolet irradiation lamp 12 fail to provide anoutput of ultraviolet radiation, either due to a burnout of the lamp 12itself or a failure of a power connection, perhaps by a blown fuse, tothe coupling 30, ultraviolet radiation will no longer be emitted fromthe malfunctioning lamp 12.

As a consequence, visible light from the malfunctioning lamp 12 is alsoextinguished. As a result, the radiation output through the light tunnel60 associated with the malfunctioning lamp 12 ceases, as does thetransmission of visible light through fiberoptic filament 52. The lightoutput end 56 of the fiberoptic filament 52 for the malfunctioning lamp12 then stops emitting light. The absence of light emission at themonitoring panel 58 or 62 is thus readily observable. The operator orinspector thereby is immediately informed of the malfunction of the lamp12, as well as the specific location of the lamp 12 that has failed.Appropriate steps can then be taken to remedy the malfunction.

The irradiation apparatus 10 may also include an optical sensor 58A inplace of or in conjunction with the display panel 58, such as shown inFIG. 8. Optical sensor 58A is a photosensor, light detection circuit, orphotodetector at the light output end 56 of the fiberoptic filament 52,and the optical sensor 58A provides additional methods for communicatingthe lamp status to an observer. For example the optical sensor 58A may,upon receipt of a light signal from the radiation lamp 12, activate arelay to provide a lamp-on signal to an observer. In this way, eachradiation lamp 12 is provided with the ability to communicate amultitude of different types of signals and to allow interface betweenthe lamp and a variety of human-machine interface (HMI) devices, suchinterfaces being limited only by the category of devices capable ofcommunicating with the optical sensor 58A. Possible applications includea bipolar drive, a relay drive, a MOSFET drive, a high speed MOSFETdrive, and a logic drive.

An example of a circuit including an optical sensor 58A is shown in FIG.9, with particular reference to the chip labeled LM555CH. The circuitshown in FIG. 9 is a simple on-off photo switch that does not require asignal comparator. In the depicted schematic, the output from the chiplabeled LM555CH goes high when the optical sensor is not blocked, whilethe inverting variation (shown in the lower left corner of FIG. 9) goeshigh when the optical sensor is blocked.

Use of the optical sensor 58A does not introduce any electrical noiseinto the signal coming from the radiation lamp 12 since the opticalsensor 58A is isolated from the electrical power of the radiation lamp12 as the communication between the radiation lamp 12 and the opticalsensor 58A is only through light.

Undoubtedly, numerous variations and modifications of the invention willbecome readily apparent to those familiar with ultraviolet lightirradiation systems. Accordingly, the scope of the invention should notbe construed as limited to the specific embodiments described, butrather is defined in the claims appended hereto.

INDUSTRIAL APPLICABILITY

This invention may be industrially applied to the development,manufacture, and use of systems for displaying the status of operationof shielded ultraviolet irradiation lamps using fiberoptic filaments.

1. In an ultraviolet light irradiation apparatus including an ultraviolet light irradiation lamp concealed from view and an external, observable lamp status display panel, the improvement comprising a fiberoptic lamp status display filament having a first end terminated in optical communication with the ultraviolet lamp and an opposite, second end terminated at a light sensor in the lamp status display panel.
 2. An ultraviolet light irradiation apparatus according to claim 1 further comprising a ceramic base with a tunnel therethrough and which receives the ultraviolet radiation lamp, a lamp connector that seats the ceramic base and supplies electrical operating power to the lamp, and the first end of the lamp status display filament terminates in the lamp connector so that the first end of the filament is in optical communication with the lamp through the tunnel.
 3. An ultraviolet light irradiation apparatus according to claim 1 further comprising a ceramic base that has a lamp receiving end and an opposing power input end, and further characterized in that a linearly aligned tunnel is defined through the base between the opposing ends thereof, and the tunnel conducts visible and ultraviolet light from the ultraviolet irradiation lamp to the first end of the fiberoptic filament.
 4. An ultraviolet light irradiation apparatus according to claim 1 wherein the fiberoptic filament is fabricated of a material that passes visible light while blocking ultraviolet radiation.
 5. An ultraviolet light irradiation apparatus according to claim 1 wherein the light sensor is a light detection circuit.
 6. A power status indicator for an ultraviolet irradiation lamp mounted in a base that has a lamp receiving end and a power input end and which is coupled to a lamp connector supplied with electrical power from a power cord connected thereto comprising a straight linear light tunnel defined in the base and extending between the lamp receiving end and the power input end thereof and in optical communication with the ultraviolet lamp, and a fiberoptic filament having a light input end terminating in the lamp connector in optical communication with the light tunnel through the base and an opposite light output end that provides a lamp status display to an observer, the lamp status display including a photosensor in optical communication with the light output of the fiberoptic filament.
 7. A power status indicator according to claim 6 wherein the fiberoptic filament suppresses transmission of ultraviolet radiation while facilitating transmission of visible light.
 8. A power status indicator according to claim 6 wherein the base and the lamp connector are releaseably joined together.
 9. In an array of ultraviolet light irradiation lamps each of which is mounted in a separate base and which is provided with electrical operating power through a separate lamp connector dedicated thereto, the improvement comprising a straight light tunnel through each of the bases in optical communication with the ultraviolet lamp and a separate fiberoptic filament, each having a light input end terminated in a single one of the lamp connectors and in optical communication with a single one of the light tunnels and an opposite display end terminated in a light sensing circuit in a status display panel.
 10. An array of ultraviolet light irradiation lamps according to claim 9 wherein each of the fiberoptic filaments transmits visible light and attenuates ultraviolet radiation. 